Design Of Fiber Grating Slope Monitoring System

With the rapid development of national economy, a number of new highway and railway projects come out. Many of ore were mined becoming tailings. Safe and stable operation of various projects has become a priority. On both sides of dam, railway and highway, some inclined slopes can always been seen, one side of tailings dam is also inclined slope, which is one of the main factors engineering safety operations and its stability directly affects the normal operation of the project. Therefore, monitoring slope stability has become very important. But in our country the main means of security monitoring mainly rely on electrical signals to transmit information, these devices can operate normally on the highway without electrical components, but used along the railway, even high-speed railway, because of the presence of many electrical components and even high-voltage transmission lines along the railway, all kinds of electromagnetic interference generated makes electrical signals monitoring look a little less. Moreover, the electrical signal is easily limited by weather, and short transmission distance is one of the defects. Therefore, there is an urgent need to develop a monitoring system which has advantages of anti-electromagnetic interference capability, long life and small external environment impact.Based on this demand, a real-time slope monitoring system basing on fiber grating angle, crack, permeate pressure sensors is designed. The design ideas is to use fiber grating sensitivity to external stress and judge slope stability through the centre wavelength of each sensor which can get angle, permeation pressure information. The main contents are as follows:First, design fiber grating angle sensor and cracks sensor. Since the center wavelength of FBG is easily affected by outside temperature and stress, the sensor is mainly used the center wavelength to determine stress. So it is necessary to take appropriate measures to eliminate temperature effect.Then, design slope monitoring system based on fiber Bragg grating sensors. Under overall system solutions, hardware is selected and circuit is designed. STM32F205 is used as the core of high-performance RISC computer, and one fast fiber grating demodulation module is also adopted. GPRS module is used to achieve long distance transmission.Finally, first test the performance of the sensor. Doing experiments proves that method to eliminate temperature effects is obvious, and angle and crack sensor can accurately measure the angle tilting and the size of crack. Then, basing on Lunan iron ore tailings, testing the entire system under engineering environment, fiber grating sensors in slope monitoring system have good results, the system is stable and can monitor angle, cracks and osmotic pressure which provides a reliable solution for slope monitoring.Design and implementation of fiber grating slope monitoring system can better solve the current problems in slope monitoring, improve the ability to predict danger, strengthen security monitoring capacity, the system has high practical value.